1. Field of the Invention
The present invention relates to an optical engine of projector, and more particularly, to a cooling apparatus for optical engine assembly.
2. Description of the Prior Art
As the optical-electronic technology develops in a fast phase, the general projecting display device usually uses the high power bulb as the light source to project a clearer image with high brightness. However, the high power bulb also produces high temperature at the same time. Therefore, a fan is used for cooling such prior-art projecting display device to avoid the rise in temperature and the deterioration of optical components due to the light incidence of the bulb. Although the fan is used for the heat dissipation, it also generates noises. Therefore, the improvement of heat dissipation with a limited fan becomes an important research and development topic for the industry.
Please refer to FIG. 1, which shows an imaging assembly 10 of an optical engine of a prior-art display device, and a projecting lamp (not shown in the figure) is installed under the imaging assembly 10. The white beam emitted from the projecting lamp as shown in FIG. 2 is divided into three colors: red, blue, and green by a X-plate 12 inside the housing 11 of the image assembly 10, and each colored light is guided into three polarizer modules 13, 14, 15 each comprised of a polarizer and a half wave plate, and modulated by three sets of modulating units comprised of three light valves 161, 162, 163, and synthesized by a X-cube 17, and finally projected onto a screen from a projection lens (not shown in the figure) disposed at the front end of the X-cube 17.
The high intensity light projected by the foregoing high-power light bulb passes through the optical components such as the X-plate 12, three polarizer modules 13, 14, 15, three light valves 161, 162, 163 and the X-cube 17, and will produce heat of high temperature. Heat dissipation must be performed, so that the temperature will not exceed the suitable operating temperature range, or else affecting the properties of the optical components and deteriorating the color and optical evenness of the image as well as lowering the quality of projection, or even damaging the expensive optical components in some serious cases. Although the high intensity light emitted by the foregoing high-power projecting lamp will heat up the temperature of each optical component along the optical path, this invention only intends to solve the heat dissipation problem of the optical components in the reflecting LCD image assembly 10, and the description of the heat dissipation of the related prior-art imaging assembly 10 will be given below.
The three light valves 161, 162, 163 of the aforementioned prior-art assembly 10 are respectively fixed onto the front and both sides of the housing 11, and two through holes 111, 112 with aslant surface are disposed in the front section of the housing 11, and fans 181, 182 is respectively mounted onto each hole such that the fans 181, 182 are disposed between the three light valves 161, 162, 163 for sucking the air from the outside. The air is blown to the related optical components between the three sets of modulating units, and the direction of airflow is shown by the arrows in FIG. 2. The air flow dissipates the heat produced by the X-plate 12, the polarizer modules 13, 14, 15, the light valves 161, 162, 163 and the X-cube 17 in the housing 11. However, since the top of the housing 11 is sealed and only the bottom has openings, and the three light valves 161, 162, 163 are fixed onto the side of the housing 11, the air is blown through the three sets of modulating units. Most of the air from the fans 181, 182 through the three sets of modulating units can only be blown to the optical components such as the X-plate 12, the polarizer modules 13, 15 on both sides, and the X-cube 17. It is difficult for the air to be blown into the corners of the polarizer module 14 for a through heat dissipation. In the meantime, only a small portion of the bouncing air is blown to the surfaces of the three light valves 161, 162, 163 and the air is unable to blow onto the external surface of the housing 11. It thus causes the uneven airflow in the housing 11, and makes the light valves 161, 162, 163 and the polarizer module 14 unable to effectively dissipate the heat which affects the functions of the optical components or even deteriorates the optical components due to the high temperature. In addition, the two fans 181, 182 used in the imaging assembly 10, also increases the noise, that lowers the quality of the entire projecting display device.
The objective of this invention is to provide a cooling apparatus for optical engine assembly that evenly distributes the airflow inside and outside the imaging assembly to enhance the heat dissipation efficiency of the optical components and extend the life of the optical components.
Another objective of this invention is to provide a cooling apparatus for optical engine assembly that comes with a fan to effectively use the heat dissipation efficiency of the airflow to reduce the use of fans, lower the cost, noise, and complexity of circuit control.
Another further objective of this invention is to provide a cooling apparatus for optical engine assembly that uses a changing direction diversion board to interfere the horizontal airflow and the vertical airflow in order to enhance the heat dissipation effect.
To achieve the above objectives, the present invention sucks in the air from the fan at the top of the imaging assembly of the optical engine and blows the air from the air duct device downward. Some of the air is guided by the diversion board, aslant guiding surface, and aslant isolating board of the air duct device and blown into the imaging assembly for cooling the optical components. Some of the air is guided through a first air duct, a second air duct, and a third air duct extended from the outside of this main body respectively to the outer surface of the light valves for beat dissipation. Further, some of the airflow is guided into a branch air duct and blown to a vent of the imaging assembly of the optical engine. By means of the changing direction diversion board, the airflow is guided towards the polarizer module such that the heat at the projection lens of the polarizer module can fully be dissipated, and flown out from a vent on the other side. It produces a lateral airflow, and interferes with the vertical airflow blown directly downward from the fan into the interior of the housing.
To make it easier for our examiner to understand the objective of the invention, its structure, innovative features, and performance, we use a preferred embodiment together with the attached drawings for the detailed description of the invention.